1. Field of the Invention
The present invention relates to recorders, and more particularly to recorders of the type having a flat bed.
This type of recorder is generally of a construction in which a chart, when recording, is held flat on a flat bed to enable convenient viewing of the trace of recording. The size of the flat bed is suitably determined for this purpose, and a blank chart is stored in a suitable holder disposed typically in the back of the flat bed. Then, when a chart is desired to be placed in the holder or withdrawn therefrom, the flat bed is moved to provide access to the holder. In replacing the chart it is necessary to engage and disengage the chart perforations with and from the sprocket teeth of a chart feed wheel which is usually attached to the recorder case. For these reasons, it is desirable to provide a recorder having an arrangement capable of simplifying chart replacement.
2. Description of the Prior Art
The prior art flat bed type recorder is of a construction in which the chart feed wheel is installed independent of the movement of the flat bed. It rotates to draw the chart from the back of the flat bed and move the chart on the top surface of the flat bed. One disadvantage to this type of construction is that when the chart is replaced, because the chart must be passed through the back of the chart feed wheel, the chart perforations must be engaged with or disengaged from the sprocket teeth when moving the flat bed. This has hampered prompt replacement of the chart. This disadvantage is especially prevalent on recorders mounted vertically on a rack. Another disadvantage is that with the prior art recorder it is virtually impossible to unload the chart before its end unless the chart is torn off at that point. Furthermore, to have access to the chart storage area, it is necessary to swing out of the flat bed. In practice, the flat bed, when carrying a chart on it, cannot easily be opened, which makes it difficult to see how much chart material remains in the storage space.